There presently exist bypass valve constructions that are meant to be installed under a bathroom or kitchen sink. Under sinks one normally finds two valves that are attached to pipes extending through the wall below the sink. The left side valve is normally connected to the hot water supply and the right side valve is normally connected to the cold water supply. These valves are also called angle stops because the water flow makes a turn in them from generally horizontal to vertical and when one closes these valves it stops the water flow to the sink fixture. Attached to these valves one finds hoses or pipes that connect to the sink fixture.
If no bypass valve is installed the water in the hot supply pipe over time will cool if the fixture is not opened so when one turns on the hot water faucet one has to wait for this cooled hot water to be emptied out of the line before hot water from the hot water source, either a hot water tank or tank-less water heater, reaches the sink fixture. During this waiting period water is being wasting as the cooled hot water in the line goes down the drain. To save this wasted water and the wait time, a bypass valve can be installed under the sink which maintains hot water to the fixture. There are several valves on the market today that do this and the present invention proposes an improvement in the bypass valve that uses a different technique to maintain hot water at the fixture.
The way these bypass valves work is they react to changes in the temperature of the water in the hot water supply line to the fixture. To do this they are installed between the hot water supply to the fixture and the cold water supply to the fixture. When one of these valves is installed a flow path is created that allows water from the hot water supply to the fixture to flow to the cold water supply to the fixture. This flow path is a loop since the cold water supply to the fixture is also the cold water supply to the hot water source (tank or tankless heater).
Simply connecting the hot and cold supplies may, not maintain hot water at the fixture. A pump is used to establish a flow from the hot supply to the cold supply. Normally the pump is installed into either the hot water line that leaves the heating source or in the cold water supply line to the heating source. The pump can run continuously or intermittently based on time or demand. Any time the pump is running and the under-sink valve opens water flows through the bypass from the hot supply of the fixture into the cold water supply of the fixture. Another way flow is initiated is to open the hot or cold faucets at the fixture. When this happens water could flow through the bypass and either cold water would cross over to the hot water faucet or hot water would cross over to the cold water faucet. To keep cold water from crossing over when the hot water faucet is opened, a check valve is included in the bypass valve. This stops the flow of cold water to the hot water faucet.
Accordingly, it is an object of the present invention to provide an improved bypass valve that prevents the hot water from crossing over when the cold water faucet is opened. In accordance with the present invention, a bi-metal coil valve is used that closes the internal bypass port in the valve when hot water reaches the valve (coil).